Infrastructure Engineering - Research Publications

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Author: Duffield, Colin × Author: Miramini, Seyedsaeed × Author: Sofi, Massoud × Start date: 2020 ×

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    Infrared thermography detection of delamination in bottom of concrete bridge decks
    Raja, BNK ; Miramini, S ; Duffield, C ; Sofi, M ; Zhang, L (JOHN WILEY & SONS LTD, 2022-03)
    Infrared thermography (IRT) has been widely used in detecting the subsurface delamination of bridge deck. However, IRT inspection on delamination zones of the bridge deck which have limited exposure to direct solar radiation (e.g., the bottom surface of the bridge deck) is rather challenging due to the relatively low thermal contrast (∆T) development in these zones. Therefore, the purpose of this study is to conduct a series of experimental studies in conjunction with numerical modeling for investigating the effectiveness of IRT in delamination detection of bridge deck components which are normally not exposed to direct solar radiation. Specially, the effects of different environmental conditions, thickness of bridge deck, and defect characteristics on the absolute thermal contrast (∆T) development were systematically investigated. The results show that IRT can effectively detect the subsurface delamination of concrete bridge deck located in regions that are not exposed to the direct solar radiation. In addition, the development of detectable thermal contrast (>0.5°C) is much dependent on the rate of change in ambient temperature with a suitable detection period between 8 am and 4 pm. Furthermore, it shows that the value of ∆T increases with the increase of bridge deck thickness and delamination size.
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    The influence of ambient environmental conditions in detecting bridge concrete deck delamination using infrared thermography (IRT)
    Raja, BNK ; Miramini, S ; Duffield, C ; Sofi, M ; Mendis, P ; Zhang, L (Wiley, 2020-04-01)
    Delamination is a serious form of deterioration in concrete bridge decks. Infrared thermography (IRT) is an advance non‐destructive testing method for concrete bridge deck delamination detection by capturing the absolute thermal contrast (ΔT) on the concrete surface caused by the disruption in heat flow due to subsurface defects. However, as the ambient environmental conditions (e.g. wind velocity and solar radiation) of a bridge could significantly affect the measurement outcomes of IRT, the optimal times for infrared data collection are still unclear. In this paper, a series of experimental and numerical studies were carried out to investigate the effects of the rate of heat flux and wind velocity on ΔT on the surface of bridge decks with the aim of identifying the optimal inspection times for different geometry characteristics of delamination (i.e. size and depth). The developed model is firstly validated by the experimental data and then a series of parametric studies were carried out. The result shows that the heat flux rate plays an important role in the development of ΔT on concrete surface, especially for a relatively shallow and small size delamination. However, the influence of heat flux rate gradually diminishes with the increase in size and depth of delamination. In addition, it demonstrates that there is a positive linear correlation between the total heat energy (external irradiation) and square of the delamination depth. The current research represents an important step towards the development of an effective and efficient way for defect detection using IRT.